Focus points of post-closure monitoring in geological disposal

Murakami, Hiroaki  ; Watanabe, Yusuke  ; Fukuda, Kenji; Iwatsuki, Teruki  

To understand geological-environment stability at the deep underground, it is important to monitor changes in EdZ. Monitoring after closure of underground facilities is particularly important, however few studies have been reported on post-closure monitoring. We considered about focus points of post-closure monitoring by using hydrochemical data of groundwater in/around Mizunami Underground Research Laboratory. In highly permeable strata such as conglomerate formation, the source of groundwater changes due to URL construction and operation. In this section after URL closure, the water pressure will recover and the source of the groundwater will change again. Therefore, the section greatly influenced by the facility construction and operation should be chosen for post-closure monitoring.